Uncovering the photoexcited dynamics in bis(acyl)phosphine oxide photoinitiators.

ABSTRACT: Acylphosphine oxide photoinitiators, such as phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide (BAPO) and diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide (TPO), are widely used as sensitisers in UV polymerisation applications due to their favourable properties for UV lithography. However, the underlying photophysical and photochemical mechanisms that govern their performance remain poorly understood. In this study, we systematically investigate these compounds using steady-state and time-resolved fluorescence, as well as electronic and infrared transient absorption spectroscopic techniques. The results show that the lowest electronic excitation of both BAPO and TPO leads to a rapid intersystem crossing (ISC) into the hot triplet manifold-which rapidly generates radicals, further undergoing

SUBMITTER: Navickas M 

PROVIDER: S-EPMC12427173 | biostudies-literature | 2025 Sep

REPOSITORIES: biostudies-literature